As method of forming a new semiconductor layer on a semiconductor substrate, an epitaxial growth method has been widely used in a semiconductor manufacturing process. For example, the epitaxial growth method is sometimes used in forming a new silicon (Si) single crystalline layer (Si epitaxial layer) on a single-crystallized Si substrate.
For example, there is known a method which includes forming an amorphous Si layer on a single-crystallized Si substrate, by performing a thermal treatment on the formed amorphous Si layer and performing a solid-phase epitaxial growth using an exposed surface of the single-crystallized Si as a seed.
In addition to Si, a silicon-germanium (SiGe) or a germanium (Ge) is getting a lot of attention as a semiconductor material as SiGe or Ge can further improve performance of a semiconductor integrated circuit device. In other words, SiGe and Ge materials have higher carrier mobility than Si. As such, the use of the SiGe or Ge material further increases an operating speed of a transistor.
For example, there is known a method of growing a SiGe epitaxial layer on a single-crystallized Si substrate.
However, as a homo-epitaxial growth, for example, when a Si epitaxial layer is grown on the single-crystallized Si substrate, “pyramid-like sharp portions” (also referred to as “facets”) are generated on a surface of the Si epitaxial layer.
In addition, as a hetero-epitaxial growth, for example, when a SiGe epitaxial layer is grown on a single-crystallized Si substrate, a “roughness” (also referred to as a “cross hatch pattern”) is generated on a surface of the SiGe epitaxial layer due to a difference between lattice constants of Si and SiGe.
In addition, an amorphous film is hard to grow on an underlying single-crystallized substrate. This is because the amorphous film deposited on the underlying single crystallized substrate drags a lattice constant of the underlying single-crystallized substrate.